Wetland vegetation in the sub(alpine) zone of the West Carpathians (Poland, Slovakia) was studied with particular reference to the following questions: (i) What are the main types of (sub)alpine fen, bog and spring vegetation above the timberline in the West Carpathians? (ii) Which major environmental gradients are associated with the variation in floristic composition? (iii) What determines the α-diversity of bryophytes and vascular plants in the different vegetation types? Vegetation plots were sampled and direct measurements of certain environmental characteristics recorded. Cluster analysis was used to distinguish the vegetation types, DCA and CCA to reveal the main vegetation gradients and environmental factors, and general regression models to identify the factors determining the α-diversity. Classification at the level of 12 clusters was ecologically and syntaxonomically interpretable. Two associations not mentioned in the most recent vegetation survey of Slovakia were distinguished and the syntaxonomical positions of others revised. The synthesis of collected and published vegetation data for the two countries has modified the classification concept of (sub)alpine wetlands in the West Carpathians. Whereas pH predominantly determined floristic differences among classes, different factors governed the species composition within classes. While the diversity of the vegetation of springs (Montio-Cardaminetea) was mostly determined by water chemistry, altitude and geomorphology appeared to be more important within fens and bogs. The species richness of spring vegetation was more influenced by mineral richness than water pH and for bryophyte richness the slope inclination was also important. The species richness of fens and bogs increased with pH. It is concluded that the ecological gradients influencing the floristic composition and species richness of (sub)alpine wetlands are strongly habitat-dependent.
Utricularia stygia Thor and U. intermedia Hayne are aquatic carnivorous plants with distinctly dimorphic shoots. Investment in carnivory and the morphometric characteristics of both types of shoots of these plants were determined in dense stands growing in shallow dystrophic waters in the Třeboň basin, Czech Republic, and their possible ecological regulation and interspecific differences considered. Vertical profiles of chemical and physical microhabitat factors were measured in these stands in order to differentiate key microhabitat factors associated with photosynthetic and carnivorous shoots. Total dry biomass of both species in dense stands ranged between 2.4–97.0 g·m–2. The percentage of carnivorous shoots in the total biomass, which was used as a measure of the investment in carnivory, ranged from 40–59% and that of traps from 18–29% in both species. The high percentage of total biomass made up of carnivorous shoots in both species indicates both a high structural investment in carnivory and high maintenance costs. As the mean length of the main carnivorous shoots and trap number per plant in carnivorous shoots in both species differed highly significantly between sites, it is probable that the investment in carnivory is determined by ecological factors with low water level one of the potentially most important. Marked differences were found only in [O2] between the 1–3 cm deep free-water zone with green photosynthetic shoots of both species and the 10 cm deep loose sediment with chlorophyll-free carnivorous shoots with traps (range 1.7–7.2 vs. 0.0–0.8 mg·l–1). The waters can be characterized as mesotrophic. Though anoxia occurred consistently at a depth of 10 cm in loose sediment at all U. stygia and U. intermedia sites the carnivorous shoots of both species growing in this microhabitat are able to survive and do not avoid this microhabitat.